Method of finishing paper



UNITED STATES PATENT OFFICE.

QME'IHOD'OF FINISHING PAPER.

Specification of Letters Patent.

Patented Dec.21, 1920.

No Drawing. Original application filedMarch 5, 1919, SeriaLNo. 280,810. Divided and this application .filed October 30,1919. Serial No. 334,587.

To all whom it may concern."

Be it known that I, CHARLES W. COOK, a citizen of the United States, residing at Holyoke, in the county of Hampden and State of Massachusetts, have invented certain new and useful Improvements in Methods of Finishing Paper, of which the following is a specification.

My invention relates to a method of finishing paper and more particularly for producing a fabric finish on high grade papers such as are used for writing paper and covers, the present application being a division of my co-pending application filed March 5, 1919 Serial No. 280,810.

In the art of finishing paper it has been customary heretofore when a fabric finish was desired to interleaf layers of fabric backed by card board between sheets of paper and subject a stack or book, built up in this manner to pressure in a plater press. It will be apparent that the resulting impression created in the surface of the paper is a negative rather than positive reproduction of the fabric surface. Ridges on the fabric producin depressions in the paper and vice-versa. is a result the paper surface though uneven and in general simulating a fabric does not give a true fabric representation and is very indefinite and hazy in its appearance. In practice the fabrics soon lose their surface, and have to be replaced by fresh material. As a very high grade material is required the loss due to fabrics becoming unserviceable is very considerable.

Because of the unsatisfactory methods at present used in the production of fabric finishes I have evolved a method whereby a true positive impression is given the paper surface and a small quantity of fabric may be used to reproduce its pattern upon any desired quantity of paper.

Taking as an example of the application of my method, I will described the production of a linen finish. I first select a piece of linen having a surface such as I wish to reproduce upon a sheet of paper. An impression is made upon a sheet of pyroxylin, preferably by placing the linen against the surface of the pyroxylin and subjecting them to heat and pressure. The pyroxylin after cooling and hardening will be found to have a negative impression of the linen clearly defined in its surface. This sheet of pyroxylin, which may be termed the finishing plate, is then laid upon a sheet of paper and both subjected to pressure as in a plater press. The resulting impression formed in the surface of the paperisatrue positive reproduction of the linen sheet, every ridge and thread in the linen being reproduced as a ridge or thread in the surface of the paper, instead of as a depression or groove as with the old method previously referred to. As a result the finished paper is a true simulation of the linen sheet, both in appearance and to touch.

In the preparation of the finishing plate it may, in some instances, be desirable to back up the pyroxylin sheet with a layer of cardboard, but I have found that this is not always necessary and that the pyroxylin sheet may be used alone. Furthermore it is possible to produce the negative fabric impression on both sides of a pyroxylin sheet, so that when placed between sheets of paper and run through the press, both sides of the paper is finished at one pressing operation.

In practice it is possible to make a large number of finishing plates from a single sheet of fabricand after making a run the plates may be stored away for subsequent use without fear of deterioration. If a further use of the particular set of plates is not anticipated they may be used again to receive another impression, or reclaimed by any of the well known methods of reclaiming pyroxylin materials.

It is understood that, whereas I have used the term pyroxylin in both the specification and claims, any other material having pyroxylin-like characteristics may be used. Claims for the article are not presented in this application, as this subject matter is claimed in my co-pending application hereinbefore referred to.

What I claim is 1. The method of producing a fabric finish upon paper which consists in pressing a sheet of fabric against a pyroxylin surface while in a moldable condition, permitting the pyroxylin to harden, separating the fabric from the pyroxylin, subsequently pressing a sheet of paper against the formed surface of the pyroxylin, and then separating the paper from the pyroxylin.

2. The method of producing a fabric finish upon paper which consists in pressing a pyroxylin sheets,

sheet of fabric against a pyroxylin surface while in a moldable condition, thereby forming a negative impression of the fabric in the surface of the pyroxylin, permitting the pyroxylin to harden, separating the fabric from the pyroxylin, repeating this operation to provide a plurality of formed stacking a plurality of pyroxylin sheets and paper sheets in alternate layers, subjecting the stacked sheets to pressure, thereby giving a surface of each sheet a positive reproduction of the fabric surface, and subsequently separating the paper sheets from the pyroxylin sheets.

The method of producing a fabric finish upon both sides of sheets of paper which consists in pressing sheets of fabric against opposite sides of pyroxylin sheets While in a moldable condition, permitting the pyroxylin sheets to harden, separating the fabric from the pyroxylin, stacking a plurality of pyroxylin sheets and paper sheets in alternate layers, subjecting the stacked sheets to pressure, and subsequently separialting the paper sheets from the pyroxylin s eets.

Signed at Holyoke, Massachusetts, this 27th .day of October, 1919.

CHARLES W. 000K, 

